require('package1');//解析到的是 commonjs.js
require('package1/whatever'); //sub-a.js

// require('package1/sub'); //Error [ERR_PACKAGE_PATH_NOT_EXPORTED]: Package subpath './sub' is not defined by "exports" in F:\js_workplace\tutorial\node_tutorial\99node中对ES Module的支持\04.package的exports字段\01\node_modules\package1\package.json
